The present invention relates to composite particles, and a coloring composition and a resin composition using the composite particles. More particularly, the present invention relates to composite particles which not only exhibit excellent color-developing property and tinting strength but also suppress bleeding, a coloring composition obtained by dispersing the composite particles in a solvent, and a resin composition obtained by dispersing the composite particles in a rubber/resin composition.
Dyes are in general deteriorated in fastness such as light resistance, heat resistance and anti-bleeding property, but have been extensively used as a colorant for various paints, printing inks, cosmetics, rubber/resin compositions, or the like, because of clearness of color and high tinting strength thereof.
As techniques for improving such defects of the dyes, there have been proposed a method of fixing Red #226 onto the surface of inorganic particles or a nacreous pigment in various manners (Japanese Patent Application Laid-Open (KOKAI) No. 62-169716 (1987)), a method of adhering a nacreous pigment and a coloring pigment having the same surface charge to each other using a surface charge modifier (Japanese Patent Application Laid-Open (KOKAI) No. 4-332766 (1992)), a method of subjecting a mixture of a flake-like base material and a pigment and/or a dye to high-speed stirring treatment to form composite particles (Japanese Patent Application Laid-Open (KOKAI) No. 5-214257 (1993)), a method of adhering and/or fixing an organic dye or an organic pigment onto an inorganic compound using an inorganic salt (Japanese Patent Application Laid-Open (KOKAI) No. 11-35840 (1999)), or the like.
In addition, there has also been proposed a method of adhering an organic pigment onto the surface of white inorganic particles through a gluing agent such as alkoxysilanes (Japanese Patent Application Laid-Open (KOKAI) No. 2002-356625).
At present, it has been strongly required to provide composite particles which are capable of improving a dispersibility, a dispersion stability and a light resistance of paints and resin compositions, exhibit a high chromaticity and an excellent tinting strength, and suppress bleeding. However, such composite particles have not been obtained until now.
That is, in Japanese Patent Application Laid-Open (KOKAI) No. 62-169716 (1987), there are described various methods including the method of fixing sublimated Red #226 onto the surface of inorganic particles, or nacreous pigment, or the like. However, in these methods, the resultant composite particles tend to be insufficient in tinting strength and deteriorated in chromaticity inherent to dyes, and tend to cause problems such as bleeding.
In Japanese Patent Application Laid-Open (KOKAI) No. 4-332766 (1992), there is described the method of adhering a nacreous pigment and a coloring pigment having the same surface charge to each other using a surface charge modifier. However, in this method, since the adhering treatment is conducted in an aqueous medium such as water and, therefore, requires additional steps such as filtration and drying, the resultant colored nacreous composite pigment tends to be deteriorated in dispersibility, hardly exhibit a sufficient color-developing property and tinting strength, and cannot be fully prevented from bleeding.
In Japanese Patent Application Laid-Open (KOKAI) No. 5-214257 (1993), there is described the method of subjecting a mixture of a flake-like base material and a pigment and/or a dye to high-speed stirring treatment to form composite particles. However, in this method, since the ordered mixture fails to show a sufficient bonding force to the surface of particles as a nucleus, the resultant composite particles tend to be insufficient in tinting strength and effect of inhibiting occurrence of bleeding, and deteriorated in chromaticity thereof, as well as tend to suffer from flooding when formed into paints.
In Japanese Patent Application Laid-Open (KOKAI) No. 11-35840 (1999), there is described the method of adhering and/or fixing an organic dye or an organic pigment onto an inorganic compound using an inorganic salt. However, in this method, the resultant composite particles tend to be deteriorated in chromaticity and color-developing property and, therefore, may fail to show a sufficient tinting strength.
In Japanese Patent Application Laid-Open (KOKAI) No. 2002-356625, there is described the method of adhering an organic pigment onto the surface of white inorganic particles through a gluing agent such as alkoxysilanes. However, in this method, due to the organic pigment to be adhered, it may be difficult to obtain a colorant having a high chromaticity and a high tinting strength.
As a result of the present inventors' earnest study, it has been found that by coating the surface of white inorganic particles with a surface modifier and then adhering a dye or a lake (dyed lake) onto the surface of the thus coated particles, composite particles obtained are useful as a coloring composition for water-based or solvent-based paints and as a colorant for colored resin compositions, are excellent in color-developing property and tinting strength, and can be prevented from bleeding. The present invention has been attained on the basis of the finding.